Improvement of the properties of rubber nanocomposites is a challenge for the rubber industry because of the need for higher performance materials. Addition of a nanometer‐sized filler such as silicon carbide (SiC) to enhance the mechanical properties of rubber nanocomposites has rarely been attempted. The main problem associated with using SiC nanoparticles as a reinforcing natural rubber (NR) filler compound is poor dispersion of SiC in the NR matrix because of their incompatibility. To solve this problem, rubber nanocomposites were prepared with SiC that had undergone surface modification with azobisisobutyronitrile (AIBN) and used as a filler in blends of epoxidized natural rubber (ENR) and natural rubber. The effect of surface modification and ENR content on the curing characteristics, dynamic mechanical properties, morphology and heat buildup of the blends were investigated. The results showed that modification of SiC with AIBN resulted in successful bonding to the surface of SiC. It was found that modified SiC nanoparticles were well dispersed in the ENR/NR matrix, leading to good filler‐rubber interaction and improved compatibility between the rubber and filler in comparison with unmodified SiC. The mechanical properties and heat buildup when modified SiC was used as filled in ENR/NR blends were improved. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45289.

No abstract

No abstract

Many researchers have been trying to improve rubber composites because they are commonly used in a wide range of applications. Incorporation of nano-fillers in a rubber matrix is the most acceptable way to improve the mechanical and electrical properties of rubber composites. A nanometer-sized filler, such as K0.15Cr0.02Ni0.83O (KCNO), has rarely been used to improve the properties of rubber composites. Epoxidized natural rubber (ENR) was chosen for blending with KCNO nanoparticles based on its polarity and chemical resistance. The aim of this work is to investigate the effects of filler loading (0.5, 1.5, and 5 phr) on the curing characteristics, dynamic mechanical, mechanical, morphological, and dielectric properties of rubber composites. From the results, rubber vulcanizates with 1.5 phr of KCNO as filler exhibit better tensile strength and 500% modulus compared to other ENR specimens containing KCNO. ENR containing 1.5 phr of KCNO also has a higher storage modulus (E′) and glass transition temperature (Tg). The results of a microstructural characterization on a sample containing 1.5 phr of KCNO show that the natural rubber matrix and KCNO are effectively dispersed, indicating that the rubber and KCNO are likely well-matched, therefore curing simultaneously and forming a continuous phase. Furthermore, ENR containing 1.5 phr of KCNO has a greater dielectric constant (12.87 at 5 kHz) than other samples.

The utilization of cellulose nanocrystals (CNCs) extracted from natural fibers is one way to make the most use of renewable resources. Isolation of CNCs normally requires a multi‐step process that includes an alkali treatment, bleaching (using sodium chlorite) and acid hydrolysis (sulfuric or hydrochloric acid). Here, a new approach for extracting CNCs from green Luffa cylindrica biomaterial, one type of natural fiber found in tropical countries, was developed via an alkali treatment and oxidative degradation using sodium hypochlorite, without an acid hydrolysis step. The diameter and length of the obtained CNCs were about 7.5 ± 2.2 nm and 266.9 ± 25.2 nm, respectively, with a considerably higher percentage yield (40%) compared to the traditional hydrolyzed‐cellulose nanocrystals (H‐CNCs) (28%). The zeta potential of CNCs and H‐CNCs in neutral water was −29.2 ± 0.5 mV and −13.1 ± 0.5 mV, respectively. Negative charges on CNC surfaces play an important role in the reduced aggregation of CNC suspensions. The degrees of crystallinity of CNCs (78.5%) and H‐CNCs (79.2%) are comparable. Moreover, the degrees of polymerization of CNCs and H‐CNCs were 297.21 and 226.64, respectively. The method developed is considered an easy operation with low pollution, low‐cost chemicals and a time‐ and energy‐saving process. © 2022 Society of Industrial Chemistry.